DNAL1 mutations are a very rare cause of PCD [77], but male infertility has been identified in a patient with a mutation in the dynein axonemal intermediate chain gene (DNAI2), which was also missing from the sperm tail in a male PCD patient with mutations in dynein axonemal assembly factor 2 (DNAAF2) [93]. Here, DNAAF2 is linked to primary ciliary dyskinesia.